In an air-conditioning apparatus that performs air conditioning of a target space, means of the air-conditioning apparatus need to be controlled on the basis of the temperatures of a refrigerant, outside air and the like and pressure of the refrigerant and the like. Thus, a control unit (a controller) is usually disposed in a heat source unit (an outdoor unit, a heat-source-side unit) of the air-conditioning apparatus. This control unit consumes electric power by executing processing all the time during an operation of the heat source unit (air-conditioning apparatus) and also generates heat along with the operation. An example of a device in the control unit is an inverter device, for example.
The inverter device installed for changing a driving frequency in a compressor of the air-conditioning apparatus for variable-speed driving is a device having a large heat generation amount in the control unit that is caused by its operation. If the temperature of the inverter device is raised by heat generation, the inverter device might malfunction or be broken and thus, the inverter device needs to be cooled so as not to reach a high temperature. Here, the inverter device was used as an example, but the same applies to other electric devices. Hitherto, a heat sink or the like has been disposed in the control unit so that heat is emitted from the electric devices in the control unit to the heat sink and the electric devices in the control unit are cooled. Moreover, a cooling fan is used for blowing air and for cooling the heat sink, for example (See Patent Literature 1, for example).